A GaAs field effect transistor provided with a double recess attracts attentions of electronic engineers as a device, which generates a high output power and withstands a high voltage applied thereto. The double recess is composed of a wide recess and a narrow recess, each having a form of a step of stairs, and formed by etching GaAs in most cases. In order to stabilize the characteristics of the GaAs field effect transistor, it is indispensable to form the wide and narrow recesses with high accuracy. In a method for forming a double recess, which is proposed in a recent year, GaAs active layers and thin AlGaAs etching stopper layers are grown alternately and successively on a GaAs substrate, and the double recess is formed by selectively etching the aforementioned multilayered semiconductor. According to this method, the double recess can be exactly formed because of the presence of the etching stopper layers, and a drain current, a threshold voltage and a gate breakdown voltage of the field effect transistor can be stabilized. However, according to the aforementioned method, a AlGaAs etching stopper layer is exposed on the wide recess. The etching stopper layer is easily oxidized, and surface state levels arise therein, which bring about the fluctuations of the characteristics of the field effect transistors. It is extremely desirable to remove the etching stopper exposed on the wide recess.